Research shows that we are surprisingly similar to the first animals of the earth

The earliest multicellular organisms may have been missing heads, bones or arms, but pieces of them remain inside us today, new research shows.

According to a UC Riverside study, 555-million-year-old Ediacaran-era oceanic creatures share genes with today’s animals, including humans.

“None of them had heads or skeletons. Many of them probably looked like three-dimensional bath mats on the seabed, round disks sticking out,” said Mary Droser, a professor of geology at the UCR. “These animals are so strange and so different that it’s hard to assign them to modern categories of living organisms just by looking at them, and it’s not like we can extract their DNA – we can not.”

However, well-preserved fossil records have enabled Droser and the first author of the study, UCR’s recent doctorate, Scott Evans, to link the occurrence of animals and their probable behavior to genetic analysis of living things. Their research on these links was recently published in the journal Proceedings of the Royal Society B.

For their analysis, the researchers consider four animals to be representative of the more than 40 recognized species identified from the Ediacaran era. These creatures ranged in size from a few millimeters to almost a meter long.

Kimberella were teardrop-shaped creatures with one broad, rounded tip and one narrow tip that probably scraped the seabed with a string for food. Furthermore, today they can move around like snails with a ‘muscular foot’. The study included flat, oval-shaped Dickinsonia with a series of raised bands on their surface, and Tribrachidium, which immobilized their lives at the bottom of the ocean.

Ikaria was also analyzed, animals recently discovered by a team, including Evans and Droser. They were about the size of a grain of rice and represented the first bilaterians – organisms with a front, back and opening on either side connected by an intestine. Evans said that Ikaria probably had beaks, although they were not preserved in the fossil records, and that they crawled through organic material and “ate.”

All four animals were multicellular, with different cells. Most have symmetry on their left and right sides, as well as non-central nervous systems and musculature.

In addition, it appears that they were able to repair damaged body parts through a process called apoptosis. The same genes involved are key elements of human immune systems, helping to eliminate virus-infected and precancerous cells.

These animals probably have the genetic parts responsible for heads and the sensory organs that usually occur there. However, the complexity of interaction between these genes that would cause such traits has not yet been achieved.

“The fact that we can say these genes work in something that has been extinct for half a billion years is fascinating to me,” Evans said.